Characteristic (7), stochastic rousting and highly uncertain processing times are a primary concern at the operational level. Stochastic rousting are a reflection of the uncertain condition of units returned. A part will have a maximum set of processes that should be performed to restore the part to specifications. However, these routines represent a worst-case scenario, and the majority of parts will only require a sub-set of these processing steps. Highly variable processing times are also a function of the condition of the unit being returned. These additional forms of uncertainty make resource planning, scheduling, shop floor control, and materials management more difficult than in traditional manufacturing environments.